1. Field of the Invention
The present invention relates to air assist fuel injectors, and, more particularly, to inserts that guide movement of the poppets of such air assist fuel injectors and to air assist fuel injectors having solid poppets.
2. Description of the Related Art
Conventional fuel injectors are configured to deliver a quantity of fuel to a combustion cylinder of an engine. To increase combustion efficiency and decrease pollutants, it is desirable to atomize the delivered fuel. Generally speaking, atomization of fuel can be achieved by supplying high pressure fuel to conventional fuel injectors, or atomizing low pressure fuel with pressurized gas, i.e., “air assist fuel injection.”
Conventional air assist fuel injectors are typically mounted to a rail, which houses a conventional fuel injector and also defines a mount for the air assist fuel injector. The conventional fuel injector and the rail are configured such that a metered quantity of fuel is delivered from the fuel injector to the air assist fuel injector. Additionally, the rail includes a number of passageways that deliver pressurized air to the air assist fuel injector. The air assist fuel injector atomizes the low pressure fuel with the pressurized air and conveys the air and fuel mixture to the combustion chamber of an engine.
The pressurized gas and liquid fuel typically travel through the interior of a hollow poppet of conventional air assist fuel injectors, and exit the poppet through slots near a head of the poppet. The poppet is reciprocatable in a leg and a head of the poppet typically lifts off a seat to deliver a plume of atomized fuel from the air assist fuel injector to the combustion chamber of an engine. The seat and leg of such conventional air assist fuel injectors each include a bearing surface to guide movement of the poppet. Unfortunately, the finish dimensions of these bearing surfaces are typically set during complex and time consuming grinding operations. If these finish dimensions are not precise, the air assist fuel injector may fail or function improperly because of improper alignment of the poppet. Additionally, the hollow poppets of such conventional air assist fuel injectors are also difficult to manufacture.